Short answers, pulled from the story.
Quantum field theory (QFT) is a theoretical framework that combines classical field theory, quantum mechanics, and special relativity. It describes subatomic particles as excited states of underlying quantum fields and is the basis of the Standard Model of elementary particles, which covers all known fundamental interactions except gravity.
Paul Dirac coined the term quantum electrodynamics (QED) in his seminal 1927 paper "The quantum theory of the emission and absorption of radiation." The theory was later made mathematically consistent around 1950 through the renormalization procedures developed by Julian Schwinger, Richard Feynman, Freeman Dyson, and Shinichiro Tomonaga.
Renormalization is a systematic procedure for removing infinite quantities from perturbative calculations in QFT by replacing unobservable bare values of mass and charge with their finite experimentally measured values. It was developed around 1950 and allowed calculations of the electron's anomalous magnetic moment and vacuum polarization to match experimental measurements to a remarkable degree.
The Higgs boson was detected at CERN in 2012, marking the complete experimental confirmation of all constituents predicted by the Standard Model. The Higgs boson is central to the mechanism of spontaneous symmetry breaking, which explains how the W and Z bosons acquire mass while gauge symmetry is preserved.
Gravity is non-renormalizable within QFT, meaning that perturbative calculations produce infinities that cannot be removed by redefining any finite number of physical parameters. This distinguishes it from the other fundamental interactions, which are all described by renormalizable QFTs within the Standard Model.
Paul Dirac and others realized by 1929 that negative energy states implied by the Dirac equation required the existence of a particle with the same mass as the electron but opposite electric charge. Carl David Anderson confirmed this prediction by detecting positrons in cosmic rays in 1932.